Bike Frame Size Calculator
Find your perfect bike frame size based on your height and inseam measurements. Get accurate sizing recommendations for road bikes, mountain bikes, and hybrid bikes with detailed size charts and fit guidance.
How do I measure my inseam for bike sizing?
Stand barefoot with your back against a wall, feet 6-8 inches apart. Place a book between your legs, spine up, pulled firmly into your crotch (simulating a bike saddle). Mark the wall at the top of the book, then measure from the floor to the mark. This is your inseam length. Measure in cm for best accuracy.
What bike frame size do I need for my height?
For road bikes: 5'0"-5'3" = 47-49cm (XXS/XS), 5'3"-5'6" = 50-52cm (S), 5'6"-5'9" = 53-55cm (M), 5'9"-6'0" = 56-58cm (L), 6'0"-6'3" = 58-60cm (XL), 6'3"+ = 61cm+ (XXL). However, inseam is more accurate than height alone, and proportions vary by person.
What is the difference between road bike and mountain bike sizing?
Road bikes use larger frame sizes (typically 48-62cm) and are sized to fit closely for aerodynamics and efficiency. Mountain bikes use smaller frames (typically 13-23 inches or XS-XXL) for better maneuverability, standover clearance, and control on technical terrain. Mountain bike frames run about 10-15cm smaller than road bikes for the same rider.
Should I size up or down if I'm between bike sizes?
If between sizes: Choose SMALLER for: sportier/aggressive riding, better handling, racing, more standover clearance. Choose LARGER for: comfort/touring, longer rides, more stability, reach flexibility with stem adjustments. When in doubt, smaller is often better as you can add a longer stem, but you can't shorten a frame.
How important is standover height on a bike?
Standover height (clearance between the top tube and your crotch when standing over the bike) is crucial for safety and comfort. You should have 2-5cm clearance on a road bike and 5-10cm on a mountain bike. Insufficient standover clearance can cause injury when dismounting quickly or during crashes.
Can I adjust a bike that doesn't fit perfectly?
Minor fit issues can be adjusted: Seat height (most critical and easily adjusted), seat fore/aft position, handlebar height (with spacers/stem changes), and reach (with different stem length). However, the frame size is the foundation - if the frame is too far off, no amount of adjustment will make it comfortable or efficient.
What size hybrid or commuter bike do I need?
Hybrid bikes typically use S/M/L/XL sizing between road and mountain bikes. For comfort: 5'0"-5'4" = XS/S, 5'4"-5'8" = S/M, 5'8"-6'0" = M/L, 6'0"-6'3" = L/XL, 6'3"+ = XL/XXL. Hybrids are more forgiving on sizing since they prioritize comfort over performance. Test ride with an upright, comfortable position.